Series flash-lamp unit



July 29, 1969 H. G. GANsER ET AL 3,458,270 SEIES FLASH-LAMP UNlT Filed .June 2, 1967 2 Sheets-Sheet l HANS aslmsLNTOR"i ERHARD KAuER -IIYHANS 1. LYnnN AGEN - `Iuly 29, 1969 v HA G, GANSER ET AL 3,458,270

SERIES FLASH-LAM1` UNIT Filed June :3, 1967 2 Sheets-Sheet 2 MWEN'RRE HANS G.GANSER ERHARD KAUER BYHANS J. lYDIN AGENT United States Patent O 3,458,270 SERIES FLASH-LAMP UNIT Haus Gunther Ganser, Stolberg, and Erhard Kauer and Hans Jurgen Lydtin, Aachen, Germany, assignors, by mesne assignments, to U.S. Philips Corporation, New York, N.Y., a corporation of Delaware Filed June 2, 1967, Ser. No. 643,158 Claims priority, applicationrmany, June 4, 1966,

N Int. Cl. F211( 5/02; G0311 15/04, 9/70 U.S. Cl. 431-95 3 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a series iiash unit employing several flashlight lamps which are provided in it and are to be fired successively, in which part of the thermal energy developed in firing a ashlight lamp actuates a switch for making the next flashlight lamp ready for operation.

In the known ash units a bimetallic element is associated with every ilashlight lamp and is deformed by the radiant energy generated in firing a ilashlight lamp. This bimetallic element actuates 4a switching device which is constructed from several parts, of which at least one is spring-loaded. After the actuation by the bimetallic elements the two parts of the switching device to be connected are automatically forced against each other. In the known series ilash units, the fired ashlight lamps are exchanged for new ones.

It is the object of the invention to provide a series ilash unit of a very simple construction without movable switching components and which can be manufactured cheaply and can be thrown away after the lamps have been tired.

The series ilash unit according to the invention is characterized in that every switch is spaced from the surface' of the associated lamp and comprises a switching member which connects two electrodes; the member lbecomes low-ohmic and conductive only as a result of radiant heat generated in firing a lamp and thereby connects the electrodes in an electrically conductive manner.

In contrast with the known series ash unit, the switching member in the flash unit, according to the invention, is spaced from the surface of the lamp and is preferably arranged on the wall of the housing; this switch responds to the thermal radiation, and then connects the two electrodes of the switch directly together without any intermediate steps. So a multiple switching device as in the known flash unit is not necessary.

According to a first embodiment, the switch which responds to thermal radiation is in the form of a fuse switch, which consists of a low-melting-point metal alloy which is kept spaced from the electrodes by a low-meltingpoint insulating layer. The metal layer melting as a result of the action of the radiant heat forms a soldered joint between the electrodes.

In the unmelted condition, the low-melting-point insu lating layer of colophony, for example, ensures an absolute insulation between the electrodes of the switch to be connected. A material for the low-melting-point metal ice alloy of the switching member may be Woods alloys, Lipowitz alloys, Rose alloys, Newton alloys, which are good electrical conductors. In this example it is to be preferred that the switching member comprises a radiation-absorbing layer at least on its side facing the lamp.

According to a second embodiment of the new flashlight unit,l the switch consists of a mass which, at least on the side facing the lamp, becomes a good electrical conductor by a chemical reaction caused as a result of the action of radiant heat, and thus forms a low-ohmic connection between the electrodes. For this purpose several metal compounds are to be considered which are first high-ohmic and are then decomposed or dissociated by the absorption of radiation and then separate the low ohmic metal. It is to be noted that the released metal on cooling does not again become oxidized and high-ohmic.

Particularly favourable for this purpose is, of course, a noble metal compound. In particular a silver compound Ag2O` was, considered. It has been found, however, that the radiant energy generated is not entirely sufficient to dissociate a contact mass which consists of pure AggO so completely that a low-ohmic connection is produced. If, however, an organic binder, for example, polyvinyl resin, is added to the pure Ag2O, a chain of reduction and oxidation reactions, which occur simultaneously and exothermally, is produced by the absorbed radiant energy, the end product of which is inter alia metallic conductive silver.

Because the switches in the series flash unit according to the invention do not comprise any movable components, the electrodes of the switch to be connected are preferably included in a printed circuit which is provided on the wall of the housing of the ilash unit.

In order that the invention may `readily be carried into effect, it will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which:

FIGURE l is a front View of a series flash unit according to the invention,

FIGURE 2 is a cross-sectional view of the same unit,

FIGURE 3 shows the arrangement of the electrodes and switching contacts in the `device according to the invention,

FIGURE 4 is Va first embodiment of a fuse switch, and

FIGURES 5 and 6 show a second embodiment of a chemical switch.

The series flash unit according to the invention as shown in FIGURES l and 2 comprises a housing 1, a base 3, a reflector 5 formed as one unit, and a transparent cap 7. The base 3 is recessed for inserting the flashlight lamps either rigidly or detachably. The base 3 has such a shape, and the wall 13 of the housing comprises a printed circuit in such manner that the inserted lamps, 15, 17, 19, 21, 23 are connected in the manner as shown in FIGURE 3.

The current wires 25, 27, 29, 31, 33 of the flashlight lamps are conected t0 a common electrode 35. The current wires 41, 43, 45, 47 of the lamps are then connected by means of electrodes 49, 51, 53, 55 to switches 57, 59, 61, 63 which are shown in broken lines. By means of these switches the electrode 65 may be connected. Only the current wire 39 is directly connected to the electrode 65. When the flash unit is used, the electrodes 35 and 65 are connected to an ignition current source (battery-i-ignition capacitor) and consequently the lamps are ready for being fired.

Each of the switches 57, 59, 61 and -63- is constructed so that it is actuated by the radiant heat (arrow 67) which is generated when a lamp is red, and consequently causes the next flashlight lamp to be ready for operation. For example, as a result of firing the lamp 15, the switch 57 is actuated so that the electrodes 49 and 65 are connected l two electrodes.

In the embodiments shown in FIGURES 1 and 2,'the

3. low-ohmic. When subsequently the electrodes 35 and 65 are again connected to an ignition current source, the next vlamp 17 is fired so that the next switch 59 is "actuated by. the generated radiant heat of the lamp 17, and so on.

In the embodiment shown, the housing 1 comprises a.. connection member 69 shown in broken lines which inknown manner is provided with contacts to be connected to an ignition current source, said contacts being connected to the connections 71 and 73 of the electrodes shown in FIGURE 3. v

In a iirst embodiment shown in FIGURE 4, the switch responding to radiant heat is shown as a fuse switch. Reference numbers 49 and 65 jdenote two copper electrodes to be connected which are prepared with a low-meltingpoint, lowohmic Woods metal 75. Below this metal an insulating layer 77 of colophony' and a contact strip 79 which likewise consists of Woods metal and is provided on the wall 13 of the housing are arranged. The assembly f is covered by a radiation-absorbing blackened, foil 81.

The radiant energywhich is generated on tiring a flashlight lamp-and which impinges upon the switch'81 in the directionof thearrows 83 is absorbed by the foil in such mannerfthat the Woods rneta'l'75, 79vand`the layer 77 melt, so that a low-ohmic soldered joint is formed between the electrodes 49 and 65. y

In the second embodiment shown in FIGURES 5 .and 6, the switch which respondstto the radiant heat is a chemical switch. This switch again comprises the electrodes 65 and, for example, 49 to be connected. A mass`87 of a noble metal compound preferably AggO, vis provided, while disi switches as shown inFIGURES 4, 5,-and 6, are provided just above the lamp on the wall 13 ofthe housingfln fact,

at that area no separate vrellector'is'present between thel housing and the lamps.k

If desired, said-switches mayalterii'atively beprovided' in the vertical part of the wallof thehousing. vIn this case it is necessary, however, to perforatethe reflecor at theI areas between a lamp'and the wall of the housing, in order that a part of the. radiant energy of ya Vlamp can pass*` through the reflector S.

' What is claimedis: j

1. A flash unit in` whicha plurality of ila'shlamps are mounted to a base and are connectible between main c'on7 ductors in a primary'parallel circuitto'be tired separately ,v

conductor, the member (a) being adjacent an earlier flashable lamp, and (b) chemically reactive to radiant light energy from the flash of said'ashable lamp, whereby at least a portion of the member dissociates becoming electrically conductive.

2. A series ilash unit as Aclaimed in claim 1, characterized in that the mass consists substantially of a noble metal persed in an organic binder,`.such as polyvinyl resin, i f such mannerthat the electrodes are covered. If in-this case the radiant energy generated on firing a-ashlight lamp impinges upon the mass`487 consisting of AgZO, this silver compound which in itself ishigh-ohmic, is decom-v posed and deposits on at least the surface facing the source of radiation a layer of high-ohmic silver metal.'This silver layer is denoted 'in FIGURE 6 by 91 and it connects the In the last example, a noble metal compound was chosen; in other circumstancesv compounds of base metals may be chosen which are dissociated' by radiant heat and then deposit the readily conductingmetal. In choosing such a metal compound it should Ibe observed, however, .that the reaction products create` a reducing'atmosphere to avoidreoxidation. v

ized in that the compound is AgzO.

compound and an organic binder, for example, polyvinyl resin. y y 3. Aseries dash unit as claimed in claim 2, character- References Cited UNITED STATES PATENTS JAMES W. WESTHAVER, Frimary Examiner' U.S. Cl. X.R. 

